A Portable transceiver typically has a volume lock function that locks audio volume. Such a transceiver can avoid a sudden output of audio with an unexpectedly high volume level, for example, when a volume key is inadvertently operated.
Japanese Patent Application Laid-open No. JPH09130173 discloses an apparatus that automatically returns a volume key that has been inadvertently operated to a position at any given point in time.
The known transceiver requires that, to set the volume again after the volume has been locked, the locked state be canceled and then the volume key be operated to thereby set the locked state. Thus, the known transceiver requires complicated operations for setting again the volume to be locked. Additionally, when the volume key is inadvertently operated in the locked state, the known transceiver outputs audio at an unintentional volume level as soon as the locked state is canceled. Thus, when the volume is reset after the volume has been locked in the known transceiver, audio at an unintentional volume level will be output as soon as the locked state has been canceled.